Method of manufacturing laminated structures with multiple denier polyester core fibers, randomly oriented reinforcement fibers

Abstract

A laminated panel-type structure particularly suited for vehicle interior applications such as headliners and door panels has a multiple denier polyester fiber core and randomly oriented structural reinforcing fibers. The laminated structure has superior sound attenuation properties resulting from a core of intertwined polyester fibers of differing deniers, with preferably relatively larger denier fibers on exterior areas of the core and some bicomponent fibers, short non-woven reinforcing fiber strands which are randomly attached and intertwined with the core on opposing major sides of the core, an impervious polymer film with a low melt layer which retains the reinforcing fibers against one side of the core and is attached to a scrim layer, and a polymer web on an opposite side of the core which retains the reinforcing fiber strands on the opposing major side of the core and to which a cover stock is applied. The invention further includes a method of manufacturing the laminated structure wherein the various layers are sequentially unfurled from spools, passed through nip rollers at points of various subcombinations of materials and layers, the reinforcing fiber strands are randomly distributed on to the carrying layers from hoppers or directly from a fiber chopping device, and the completed laminated structure is cut and molded.

What is claimed is:  
     
       1. A method of manufacturing a laminate structure which can be molded into a relatively rigid structure and which is effective at absorbing sound, the method comprising the steps of: 
       providing a fibrous core containing a plurality of intertwined polyester fibers of differing denier and applying a thermoset resin to the fibrous core,  
       providing a polymer film which has a melting temperature less than a melting temperature of the fibrous core adjacent to the fibrous core,  
       putting a plurality of reinforcing non-woven fiber strands into contact with the polymer film and a first side of the fibrous core,  
       putting a plurality of reinforcing non-woven fiber strands into contact with a second side of the fibrous core generally opposite to the first side,  
       applying a polymer web over the fiber strands applied to the second side of the fibrous core, and  
       applying a cover stock to the polymer web.  
     
     
       2. The method of  claim 1  wherein the fibrous core, polymer film, and polymer web are placed in a generally co-planar arrangement by being unfurled from spools, and the nonwoven fiber strands are placed in contact with the polymer film and fibrous core by random distribution. 
     
     
       3. The method of  claim 1  further comprising the steps of applying the thermoset resin to the fibrous core by use of a resin dispensing mechanism and a coating blade, passing the fibrous core with thermoset resin through a first set of nip rollers prior to contact of a first side of the fibrous core with the fiber strands. 
     
     
       4. The method of  claim 1  further comprising the step of passing the fibrous core with the thermoset resin, fiber strands on the first side of the fibrous core and polymer film, and fiber strands and polymer web on the second side of the fibrous core through a second set of nip rollers prior to application of the cover stock to the second side of the fibrous core. 
     
     
       5. The method of  claim 1  wherein the fiber strands are applied to the polymer film and fibrous core by random distribution from a chopping mechanism operative to chop fiber rovings into strands.